GENEEAL PAET 



INTRODUCTION 



WHAT position do proteids and do we, who are built up of proteids, 

 occupy in nature ? How are we related to other chemical compounds 1 



Biologists of the present day may be divided into those who believe 

 all animal and vegetable existence to be endowed with some special 

 unexplainable force, which is the real essence of life, which causes all 

 those phenomena, characteristic of individuals who feed, propagate, and 

 die. This class of observers holds that man will never fathom the 

 vital principle. 



On the other hand we find the physico-chemical school who 

 endeavour to expound organic life by only those laws which hold good 

 for the lower inorganic compounds. This school forgets that because 

 of the very evolution of so-called inorganic compounds into organic 

 ones, which, for example, we see daily take place around us in con- 

 nection with the growth of plants, we must have in addition to the 

 old simple laws which govern the inorganic world, additional laws 

 which regulate organic existence. 1 



The view the author holds, he trusts, will bridge over the gulf 

 existing between the two schools mentioned above, namely, those of 

 the vitalists and non-vitalists. 



We have to distinguish between the origin of organic compounds 

 and that of life. To be able to make marsh-gas, alcohols, aldehydes, 

 acids, ammo-acids, peptids, peptones, and albumin, however great an 

 achievement in itself, is not the same as making life. To many people 

 a living cell consists of * protoplasm,' a substance they imagine to be 

 one exceedingly complex body. They do not realise that in a cell we 

 have a not very large number of comparatively simple compounds 

 which only collectively form the protoplasm. What constitutes life, 

 is the presence of a number of such * organic ' compounds, capable of 

 mutually reacting upon one another, and hereby giving rise to new 



1 Such new laws, for example, as are created by the asymmetric carbon atom, by 

 stereoisomers, etc. 



1 B 



